Covering-thread mechanism for sewing machines



G. S. GATCHELL. COVERING THREAD MECHANISM FOR SEWING MACHINES.

APPLICATION FILED APR. 5. I919.

Patented J an.- 17, 1922.

2 SHEETS-SHEET I.

INVENTOR WITNESSES ATTORN EY I BY/ G. S. GATGHELL. COVERING THREAD MECHANISM FOR SEWING MACHINES,

APPLICATION FILED APR. 5. 1919.

1,403,851 Patented Jan. 17, 1922.

2 SHEETSSHEET 2.

INVE TOR WITNESSES: Amalia UNITED STATES PATENT OFFICE.

GEORGE S. GATCHELL. OF BOSELLE PARK, NEW JERSEY,

assrenon TO THE SINGER MANUFACTURING COYMPAN Y, A CORPORATION 01'' EW JERSEY.

' Application filed April 5,

T 0 all whom it concern i .Be it known that l, Gnome S. GATCI-IELL, a citizen of the United States, residing at Roselle Park, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Covering- Thread-Mechanisms for Sewing Machines, of which the following is a specitication, reference being had therein to the accompanying drawings.

In sewing machines of the multi-needle seam-covering type such, for example, as used for joining and covering the abutted edges of cut knit goods, it is customary to provide, in addition to the reciprocating needles and eomplemental loop-taking means of the machine, a pair of oscillatory. threadfingers for laying covering threads back and forth across the line of seanrformation in advance of the needles, so that said threads will, in effect, be stepped over by the needles and stitched down to the'upper side of the work, thereby serving to connect the outer needle-threads and acting to cover the abutted raw edges of material at the center line of the seam in the manner illustrated in my copending applications Serial No. 185,- 446, filed August 10, 1917, and Serial No. 223,112, filed March 18, 1918, the latter having matured into Patent No. 1,365,408, January 11, 1921. I 1

In seams of this character, as heretofore made, the transversely extending portions of the covering threadsare closely grouped in pairs or lie in side-by-siderelation across the center line of the seam, so that the abutted raw edges of material are exposed at intervals between the pairs of transversely extending portions of the covering threads. The object of the present invention, therefore, is to provide an improved covering thread mechanism whereby the covering threads will be more evenly and uniformly distributed across the centerline of the seam to bettercover and bind down the abutted raw edges of material.

Further objects of the invention will appear from the following description and claims. 7

In carrying the invention into effect, provision is made for so holding the covering threads prior to the descent of the needles, that the outer needles descend in front of or, in effect, step over both covering threads while an intermediate needle steps over only one of thecovering threads, the other cover COVERING-THREAD MECHANISM FOR SERVING MACHINES.

Specification of Letters l atent. Patented Jan, 17, 1922 1919. Serial No. 287,778.

ing thread being held forwardly of the path of movement of said intermediate needle. The transversely extending port-ions of the covering threadsare thus separated where they cross the center lineof seam-formation, giving the covering threads a zi zag appear ance along the central zone of t 1e seam.

As a means for deflecting one of the covering threads forwardly of an intermediate needle, I employ in addition to the usual oscillatory covering thread-fingers, a thread positioning device secured preferably to the shank of the Presser-foot and extend ing forwardly between one of the outer needlesand an adjacent intermediate needle; said device'ipresenting a substantially vertical thread-detaining edge formed prefer ably with a thread-receiving notch into which one of thecovering threads is drawn by the movement of its oscillatory threadfinger and held in front of said intermediate needle while the remaining needles descend in front of said covering thread. During the formation of the next stitch the other of the two-thread-flngers carries its thread into engagement with the thread-positioning device with similar results As one of the thread-fingers oscillates at a slightly higher level than the other, a thread depressor is provided for bending downwardly the thread. leading from the work to the higher of the two threadfingers when in extreme outward posit-ion.

. In the accompanying drawings. Fig. 1 is a side elevation of the parts adjacent the stitching point of a sewing machine embodying the invention. Fig. 2 is a transverse verticalsection through the free end of the work-arm of the machine; showing the stitch-forming instrumentalities in elevation. Fig. 3 is a horizontal section on the line 3-3, Fig. 1. Fig. 4 is a side elevation of the resser-foot of the machine, showing the threadpositioner and thread depressor. Fig. 5 is a front elevation similar to Fig. 2 but showing how the thread-depressor is elevated by the advancing thread-finger. Fig. 6is a perspective view of the threadpositioning device. Fig. 7 is a plan view of the seam formed by the machine illustrating the even distribution-of the covering threads across the abutted raw edges of the material at the center line of the seam.

The invention will be described as embodied in the four-needle seam-covering machine disclosed in my said copendjng upplication Serial No. 185,446. Ina machine of this character the needle-bar 1 carrying a plurality of (in the present instance 4) needles n m n and n, is journaled for reciprocation in the head 2. The needles are arranged abreast transversely of the line of seamformation and cooperate with the thread-carrying looper 3 to form a seam of the usual character comprising a plurality of needle-threads formed at intervals into loops extending throughto the under side of the work and concatenated with a single looper-thread which is looped back and forth across the seam and covers the abutted raw edges of material at the center line.

The machine also embodies a pair of oscillatory thread-fingers 4 and 4" for looping a pair of flier or covering threads back and forth across theup perside of the seam. The covering thread fingers 4 and 4 are preferably formed with horizontally ,dis'posed blades and vertically disposed shanks; the latter being secured in so'cketed bosses 5 at the free ends of the thread-finger are formed at their free ends with threaddelivering eyes 9. which are connected by thread-grooves 10 with the thread-eyes 11 at the lower ends of the vertical shank portions of the thread-fingers. The blades of the thread-fingers operate at different levels, one beingslightly above the other.

Simultaneous oscillatory movements in opposite directions are imparted to the M levers 6 by means of the links 6 which con- V. reciprocation of the needles so that :each

nect the latter with one arm 6* ot'a bellcranklever fulcrumed on the headed pin 6 carried by the head 2. The other arm 6 of the bellcrank-lever is connected to suitable actuating mechanism 6 such for example as disclosed in my said copending applications, for imparting oscillatory movements to the thread-fingers at one-half the frequency of thread-finger presents its thread to the needles alternately at opposite sides of the line of seam-formation;

The customary feeding devices or dogs f are provided for advancing the work up to and beyond the stitching point. p

In mechanism of thischaract-err as here'- tofore constructed and operated, the covering threads are led in opposite directions. across. the scam. in. advance. of the needles I soethatl when the needles. rise and the feed takes place the covering threads will be shifted back of the needle paths and the needles ontheirnext descent will all pass down in front'of the covering threads, thus binding together in pairs the transversely extendingportions thereof.

In the present instanc'e,a covering thread positioning device is provided forholding one of the covering threads in advance of the path of an intermediate needle'while permitting said covering threadto assume a position in rear of the remaining needle paths. While, various thread-positioning devices may be used-to accomplishthis purpose, a simple form of such device is shown in perspective in Fig. 6. The device in this form comprises a thin blade 12 presenting a vertically disposed thread-positioning edge 13 which is preferably formed with a notch 14 into whieh the covering thread is laid by one or the other of the thread-fingers 4 and 4". The blade 12 .is supported by a -platelike shank 15 which is fixed to the positioning device 12 is placed between the outer needle. n and the adjacent intermedi-' ate needle a but closer to 'the 'latter, with the thread-engaging edge 13 and notch or throat'14 in advance of the plane of the. V needles.

When the thread-fingers are crossing the line ofseam, the covering thread leading from one or the other of the eyes ,9'will be drawn across the edge 13 of the positioning device 12 and, as the thread-finger assumes extreme position, the covering thread will slip into the notch 14 and be detained in the form of a bight or peak in advance of the path of needle a but in rear of the paths of needles W, n and n, as; shown in Figs. 2 and 3. The other covering thread will not be engaged by the positioning device and will lie in rear of all of the needlepaths. The two transversely extending portions of the covering threads will thus be separated by'the penetrative thread-loops of the intermediate needle 7; and will be evenly distributed across the abutted raw edges of the material along the center line of the seam as illustrated in Fig. 7 V e In some instances it maybe desirable to provide a device to compensate for the dif ference in elevation of the thread-eyes 9, 9, at the free ends of the covering threadfingers. Such a, device may comprise a. thread-depressor in the'form of a curved 12 blade 17. having at its. downturnedfree end 7 an upwardly and rearwardly inclined thread-engaging edge 18. The blade 17 may be supported by a cylindrical shank 19 journaled to turn in spaced bearings '20 at the lower edge of a supporting plate 21 fixed by screws 23 to: the flattened face of a collar 22, Figs. 3 and 4, clamped to the lower end of the sleeve 6"; Y i

The shank 19 is surrounded by a coiled spring 24, Fig. 1, the opposite ends of which are anchored, respectively, to one of the bearing lugs 20 and to a collar 25 fixed to the shank 19 adjacent the other of the bearing lugs 20. This spring tends to yield ingly turn the shank 19 in a direction to depress the free end ofthe curved blade 17, the inclined edge 18 of which depresses and deflects rearwardly one of the covering threads, as shown in Figs. 1 and 2. When thethread-finger 1 advances, the curved blade 17 is elevated thereby to an ineffective position wherein the blade rests yieldingly against the upper surface of the horizontal portion of the thread-finger 1 The primary purpose of the blade '17 is to compensate for the difference in elevation of the thread-eyes 9, 9, at the period of the cycle illustrated in Fig. 2, by depressing the covering thread leading from the work to the thread-finger 4* so that this covering thread will lie below and out of. contact with the thread-positioning plate 12.

It is to be understood that the use of the depressor is not absolutely essential; it being merely a desirable feature, in certain instances, where the dimenisons of the parts and the throw and extent of movement of the thread-fingers are such that the' covering thread leading to the higher of the two thread-eyes 9 is not held clear of the thread-positioning device 12.

In the seam formed by the present device it will be noted that one of the covering threads (4 extends across the seam in the front of the transverse row of needle-punctures b and in rear of the next succeeding transverse row ofv needle-punctures 6 crossing the center line 0 of the seam at (7-. The covering thread it, however, while extending transverselyof the seam in front of the needle-punctures b and behind three of the needlepunctures b, is deflected or held forwardly of an intermediate needle-puncture b and is thus separated from the covering thread (i and caused to cross the abutted raw edges of thematerial at the point (2 which is spaced from the point (Z. Thus the points where the covering threads cross the center line of the seam will be evenly distributed along the latter; the covering threads along the central zone of the seam having a zigzag appearance and effectively covering and binding down the cut thread ends along said center line.

Having thus set forth the nature of the invention, what I claim herein is 1. In a sewing machine, in combination, a plurality. of reciprocating needles, complemental loop-taking means, feeding mechanism, means for laying a covering thread back and forth across the line of seamformation, and a thread-positioner restrained against movement in the direction of feed and operating to hold the covering thread forwardly ofthe path of movement of one of said needles while others of the needles descend in advance of said covering thread.

2. In a sewing machine, in combination, a plurality of reciprocating needles, complemental loop-taking means,'feeding mechanism, means for laying a plurality of covering threads back and forth across the line of seam-formation, anda thread-positioner for holding one of the covering threads forwardly of the path of movement of an'intermediate needle while others of theneedles descend in advance of the covering threads.

3. In a sewing machine, in combination, three or more reciprocating needles, complemental loop-taking means, feeding mechanism, a pair of oscillatory thread-fingers for laying covering threads back and forth across the line of seam-formation, and a covering thread positioning device disposed between an outer and an intermediate needle and having a thread-deflecting surface in advance of and close to said intermediate needle. for holding the covering thread in advance of 'the latter while the remaining needles descend in advance of the covering threads.

'4. In a sewing machine, in combination, a plurality of reciprocating needles, complemental loop-taking means, a presser-foot, feeding mechanism, means for laying a cov- 'ering thread back and forth across the line of seam-formation, and a covering thread positioning device mounted upon said presser-foot and extending forwardly between the paths of an outer and an in termediate needle, substantially as and for the purpose specified.

5. In a sewing machine, in combination, a plurality of reciprocating needles, compleinental loop-taking means, feeding mechanism, a covering-thread laying element, and a covering-thread positioning device projecting forwardly intermediate the needle paths and adapted to engage the coveringthread in advance of the stitching point, substantially as and. for the purpose specifi d '6. In a sewing machine, in combination, a plurality'of reciprocating needles, complemental loop-taking means, feeding mechanism, a covering-thread laying element, and a covering-thread positioning device permanently disposed intermediate the needle paths and adapted to engage the covering-thread in advance of the stitching point, substantially as and for the purpose specified.

7. In a sewing machine, in combination, a plurality of reciprocating needles, complemental loop-taking means, feeding mechanism, a covering-thread laying element, and a substantially stationary coveringthread positioning device adapted to engage the covering-thread in advance of the. stitching point and hold said covering-thread in ad-.

anism, a pair, of 'covering-threadv fingers moving simultaneously in opposite. directions back and forth across the line of'seamformation in advance of the needles. and at 7 half the: frequency of reciprocation of-the 7 back and forthacross the lineof seamefor needles, and a thread-positioning device cooperating alternately with each .of' said threadfingers to detain first one andthen the other of thecovering-threads in advance of an intermediateneedle path while the re-. mammg needles descend n advance of the covering-threads. V

.;9. In a sewing machme, in combination, stitch-forming. mechamsmahcludmg a plurality of reciprocating needles and .complemental ,loop-taking means, a covering threadfingemmeans for moving salol finger mat-ion in advance of the needles, a thread positioner cooperating. with said threadfinger in one extreme position ofthelatter to holdthe covering thread in advance of one of said needles,,and a device for holding the covering. threadclear of said'thread.

positionerwhen said thread-finger is in its otherextreme position. v i

10. In a sewing machine, in combination, stitch-forming mechanism including a plurality 0freciprocating" needles and complemental loop-taking. means, a covering thread finger, means for moving said finger back and forth across the line of seam-for.- mation in advance of the needles, and a yielding device for: depressing. the covering-thread when the thread-finger is' in, an extreme position. g V y 11. In, asewing machine, in; combination, stitch-forming mechanism including av plurality of reciprocating. needles and comple-v mental loop -taking means, a covering-thread finger, means for moving said finger back and; forth across the line'of seam-formation in advance of the needle, and a yield:- ing' device for depressingv the coveringthread when the thread-finger is in an extreme position, said devicebeing disposed in the path of movement of. said threadfinger so as tobe elevatedthereby to ineffective position. 7 Y

12. In a sewing machine, in combination,

stitclrforming,mechanism including a plurality of reciprocating needles and complemental loop takingf means, feeding mechanism, a pair of oscillatory thread-fingers having thread-delivering eyes operatmg'at' different levels, and a covering-thread en} gaging device cooperating with one of said thread-fingers to shift the covering-thread ing device for detaining-the covering-thread of: one finger in advance. of an intermediate needle while the remaining needles descend in advance ofthe. covering-threads, and a coveringrthread engaging device cooperating with the other ofsaid thread-fingers tohold the thread thereof clear of the. thread-positioning device. I

14:. In a sewing machine, in. combination, a plurality of. reciprocating needles, a resser-foot, feeding mechanism, means for laying acovering thread back and forth across the line oflseam formation, and arcovering thread positioning device stationarily mounted on the .presser-foot and formed with athroat-adapted toreceive abight of covering thread and position it in advance of one of *said needles. I

15. In a sewing machine, in combination,.a plurality of reciprocating needles, a nesser-foot, feeding mechanism, means for laying a covering threadback and forth acrossthef line of seam, formation, anda stationary covering-thread positioning device mounted on the presser-foot and formed with a throat into which the covering-thread is laid by the covering-thread laying means.

In testimony wh'ereof, I have signed my name to this: specification,

GEORGE s; GATC EL 

